Fatigue Damage in Railway Steel Bridges: Approach Based on a Dynamic Train-Bridge Coupled Model

This paper evaluates the fatigue stress and damage accumulation in steel railway bridges using a dynamic coupled train-bridge system model. The system consists of a spatial vehicle model, a three-dimensional (3D) bridge model, and a wheel-rail interaction model including the effects of track irregularities. The proposed approach was validated by comparing the fatigue stresses of an existing steel railway bridge to those obtained from field structural-health-monitoring data. Fatigue evaluation of the critical structural detail in the bridge was performed on the basis of stress data resulting from the proposed approach and two conventional methods (i.e., the static-influence-line method and the moving-load method). In addition, an investigation on the effects of train speed, track irregularities, and lateral vibrations on fatigue damage and remaining service life was performed. The results show that all three considered factors can significantly affect the fatigue behavior of critical members in railway bridges. (C) 2017 American Society of Civil Engineers.